SAP BI Overview

The SAP Business Intelligence enables Online Analytical Processing (OLAP) to format the information of large amounts of operative and historical data. It is used to create various reports as per organizations need from this data. OLAP technology enables multi-dimensional analyses according to various business perspectives.

What is the difference between OLAP and OLTP?

OLTP (Online Transaction Processing) is the real time processing of data. This is the methodology used in most of the transaction processing in both SAP and non SAP systems. Here data is read from table real time, displayed in transaction and it updates the table back if data is modified in transaction.

In OLAP (Online Analytical Processing) output is given after the analysis of large amount of data. Here data is not directly fetched from the data base, instead the system analysis large amount of historical data and based on that analysis output is given. OLAP tools enable users to analyze different dimensions of multidimensional data residing in different tables. Time, Quantity etc are different dimensions.

Different Components of BI are

Source System

Any system that provides SAP BI with data is called a source system .It could be R/3 system, Another BI system, Flat files or any third party systems.

SAP (R/3) Source System has ABAP Programs named Extractors that enable the SAP (BW) System to extract data from the SAP (R/3) Source System DataSets into the Extract Structure of a DataSource.

Data that logically belongs together is stored in the SAP (R/3) Source System in the form of DataSources. A DataSource contains a number of fields in a flat structure used to transfer data into BI System. A DataSource is an object that, at the request of SAP BI System, makes data available in one of its predetermined structures.

The data from a DataSource in SAP (R/3) Source System is staged in Extract Structures. The Extract Structure contains the amount of fields that are offered by an Extractor in the SAP (R/3) Source System for the data loading process.

The data is transported from the SAP (R/3) Source System to the SAP BI System through Transfer Structure. We have the option of mentioning which all Extract Structure fields are to be transferred to the SAP BI system in Transfer Structure maintenance.
When DataSource is activated in SAP (R/3) Source System from the SAP BI
System, identical Transfer Structure like the one in the SAP (R/3) Source System is created in the SAP BI System.

SAP BI System

The SAP BI System is an enterprise-wide information hub, which analyses data from R/3 and non-R/3 application and present it in an Excel-Based user interface.

All the processes related to data staging and processing in SAP BI system is controlled, monitored and maintained through the tool Administration Workbench. And reporting is done through a tool called Business Explorer (BEx).

Data that logically belongs together is stored in the SAP BI System in the form of
InfoSources. An InfoSource contains a number of InfoObjects which structure the information needed to create InfoCubes / ODS Objects in the SAP (BW) System.
An InfoSource is an object that, at the request of SAP (BW) System, makes data available to the InfoCubes / ODS Objects.

The data from an InfoSource is staged in the Communication Structure in SAP BI System. The Communication Structure displays the structure of the InfoSource. It contains all of theInfoObjects belonging to the InfoSource of the SAP BI System. Data is updated in the InfoCubes from the Communication Structure.

InfoObjects are the basic information providers of BW. They structure the information needed to create InfoCubes/ODS Objects.

Different types of InfoObjects are,

Key Figures: Data part of an InfoObject. They are quantifiable
values. (Eg. Quantity Sold, Revenue)

Characteristics: Objects that are used to calculate and present Key
Figures. (Eg. Sales Office, Customer)

Time Characteristics: Characteristics that are assigned to the dimension of
time. (Eg. Fiscal Year, Period)

Technical Characteristics: Only of structural use within BW.
Units: Units for the Key Figures

Logical collections of data that are based on data models and business rules that are derived from the enterprise model of the SAP (R/3) System. SAP BI Systems store data in InfoAreas which can contain ODS Objects and InfoCubes.

The central objects, upon which reports and analyses in BI are based, are called InfoCubes. An InfoCube is a multidimensional data structure. An InfoCube is a set of relational tables that contains InfoObjects. An InfoCube consists of a Fact Table and a set of n Dimension Tables that define the axes of its multiple dimensions.

An Infocube contains 1 fact table, n dimension tables, n surrogate ID tables, n text tables and n master data tables.

Fact table : Contains the key figures, which are quantifiable values.

Dimension tables : Contain the characteristics that are used to analyse and
report on the key figures.

Sid tables : Specify tables in the SAP (BW) System that contain surrogate
ids. Sid tables link the master and hierarchy tables outside the
dimensions of a star schema.

Text tables : Contain descriptive text that might be time or language
dependent.

Master tables : Contains attributes that are used for presenting and navigating
reports in SAP (BW) System. They can, however, be extended
to include other data. Master tables are also time-dependent and
can be shared by multiple InfoCubes.

A basic Infocube in BI is based on snowflake schema.

Snowflake schema is a logical arrangement of tables in relational database where the entity relationship diagram represents the snowflake shape. Snowflake schema has a centralized fact table connected to multiple dimensions table. Here dimensions are normalized into multiple related tables.

Star schema consists of few fact tables referencing to any number of dimension tables. Here dimensions are denormalized with each dimension being represented by a single table. It is a kind of Snowflake schema.

There are three kinds of Infocubes,

BasicCube : It is the one on which reports and analyses in BI are based.
BasicCubes are supplied with data from one or several InfoSources.

MultiCube : A MultiCube is a superior InfoCube that combines data from several
BasicCubes / RemoteCubes, and brings it together into one context.
The MultiCube itself does not contain any data; its data comes
exclusively from the BasicCubes it is based on.

RemoteCube : A RemoteCube is an InfoCube whose transaction data is not managed
in the BI system but externally. Only the structure of the RemoteCube is defined in BW. The data is read for reporting using a BAPI from another system.

All the components mentioned until is maintained through configuration. In some scenarios we need to write little bit of code to achieve more from the configuration.

Update Rules
The update rules specify how the InfoObjects (Key Figures, Time Characteristics,
Characteristics) are updated in the DataTargets from the Communication Structure of an
InfoSource. You are therefore connecting an InfoSource with an InfoCube/ODS object.

Transfer Rules
In the transfer rules maintenance, you determine whether the communication structure is
filled with fixed values from the transfer structure fields, or using a local conversion routine.

The three types of transfer rules are,

InfoObject: The fields are transferred from the transfer structure and are not modified.
Execute the function Default transfer rules to assign fields of the transfer structure to those of the communication structure.

Constants: An InfoObject is filled by a fixed value. You could, for example, assign the fixed value 01 to the InfoObject 0COUNTRY.

Routine: Conversion routines are ABAP programs that you can create yourself. The routine always refers to just one InfoObject of the transfer structure. Data is transferred 1:1 from the Transfer Structure of the SAP (R/3) Source System into the Transfer Structure of the SAP BI System, and is then transferred into the SAP BI
System Communication Structure using the Transfer Rules